Reader/writer and manufacturing method thereof

ABSTRACT

A reader/writer comprises a circuit board, a communication control portion mounted on the circuit board and configured to perform communication with IC tags, sealing resin for sealing the communication control portion; and an antenna electrically connected to the communication control portion, in which a resin layer is disposed on the sealing resin, the resin layer having a higher adhesiveness to a conductive film used as the antenna than that of the sealing resin, and the antenna is disposed on the resin layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a reader/writer for readingand writing information on IC tags and IC cards in a non-contact mannerand a manufacturing method thereof.

2. Description of the Related Art

Nowadays, IC tags (also referred to as RFID tags) and IC cards areattached to objects of products and substances (hereafter referred to asobjects) for information management. Information about the objectsobtained from the IC tags via a reader/writer is managed using acomputer in order to improve the efficiency of business.

FIG. 1 is a plan view showing a conventional reader/writer. As shown inFIG. 1, a reader/writer 100 comprises a circuit board 101, acommunication control portion 102, a matching circuit portion 103, anantenna 104, and a mold resin 105.

The circuit board 101 includes a conductor pattern such as wiring, vias(neither is shown in the drawings), and the like. The communicationcontrol portion 102, the matching circuit portion 103, and the antenna104 are mounted on the same plane of the circuit board 101. Thecommunication control portion 102 comprises an IC chip, a passivecomponent such as LCR, and the like and the communication controlportion 102 is sealed with the mold resin 105. The communication controlportion 102 is configured to transmit/receive information with IC tagsvia the antenna 104 and electrically connected to the matching circuitportion 103.

The matching circuit portion 103 is electrically connected to theantenna 104 and the communication control portion 102. The matchingcircuit portion 103 is configured to perform matching in accordance withthe frequency of electromagnetic waves used for communication and theimpedance of input/output.

The antenna 104 is disposed on the circuit board 101 such that theantenna 104 surrounds the communication control portion 102. The antenna104 is configured to supply. IC tags with electric power andtransmit/receive information via electromagnetic induction (refer toPatent document 1, for example).

-   Patent Document 1: Japanese Laid-Open Patent Application No.    2005-12673

However, in the conventional reader/writer 100, the communicationcontrol portion 102, the matching circuit portion 103, and the antenna104 are mounted on the same plane of the circuit board 101, so that thesize of the circuit board 101 is increased. This is problematic in thatminiaturizing the reader/writer 100 is difficult.

FIG. 2 is a schematic diagram showing the relationship between amagnetic flux generated from an antenna and an eddy current. In FIG. 2,the same components as in the reader/writer 100 shown in FIG. 1 areprovided with the same numerical reference.

Further, when the circuit board 101 including the antenna 104 is assumedto be embedded in other device, the circuit board 101 may be disposed ona metallic material 106 (such as other circuit board, a battery, aframe, or the like) due to the restriction of position. In this case, amagnetic flux B₁ generated from the antenna 104 collides with themetallic material 106 and an eddy current I₁ is generated on a surfaceof the metallic material 106. Because of the eddy current I₁, a newmagnetic flux B₂ is generated and the magnetic flux B₁ is attenuated.This is problematic in that the reliability of communication between ICtags and the reader/writer 100 is reduced.

SUMMARY OF THE INVENTION

The present invention has been made in view of the aforementionedproblems.

It is a general object of the present invention to provide an improvedand useful reader/writer and a manufacturing method thereof in which theabove-mentioned problems are eliminated.

A more specific object of the present invention is to provide aminiaturized reader/writer capable of improving the reliability ofcommunication with IC tags and IC cards, and to provide a manufacturingmethod thereof.

According to one aspect, the present invention provides a reader/writercomprising: a circuit board; a communication control portion mounted onthe circuit board and configured to perform communication with IC tags;sealing resin for sealing the communication control portion; and anantenna electrically connected to the communication control portion, inwhich a resin layer is disposed on the sealing resin, the resin layerhaving a higher adhesiveness to a conductive film used as the antennathan that of the sealing resin, and the antenna is disposed on the resinlayer.

According to the present invention, the resin layer is disposed on thesealing resin for sealing the communication control portion, the resinlayer having a higher adhesiveness to the conductive film used as theantenna than that of the sealing resin. And the antenna is disposed onthe resin layer. Thus, it is possible to improve the adhesivenessbetween the resin layer and the antenna and to reduce the size of thecircuit board, thereby miniaturizing the reader/writer.

Further, in the aforementioned structure, resin containing soft magneticmetallic powder may be used as the resin layer. By disposing the resinlayer including the resin containing soft magnetic metallic powderbetween the circuit board and the antenna, it is possible to prevent thegeneration of an eddy current and improve the reliability ofcommunication between IC tags and the reader/writer.

According to another aspect, the present invention provides a method formanufacturing a reader/writer including a communication control portionfor communicating with IC tags, sealing resin for sealing thecommunication control portion, and an antenna electrically connected tothe communication control portion mounted on a circuit board. The methodcomprises the steps of: mounting the communication control portion onthe circuit board; forming the sealing resin; forming a resin layer onthe sealing resin, the resin layer having a higher adhesiveness to aconductive film used as the antenna than that of the sealing resin; andforming the antenna on the resin layer.

According to the present invention, the resin layer is formed on thesealing resin having a poor adhesiveness to the conductive film used asthe antenna, the resin layer having a higher adhesiveness to theconductive film used as the antenna than that of the sealing resin.Thus, it is possible to form the antenna above the sealing resin.

Moreover, the step of forming other resin layer including resincontaining soft magnetic metallic powder may be included between thesealing resin forming step and the resin layer forming step. By formingother resin layer including the resin containing soft magnetic metallicpowder between the sealing resin forming step and the resin layerforming step, it is possible to prevent the generation of an eddycurrent and improve the reliability of communication between IC tags andthe reader/writer.

According to the present invention, a reader/writer can be miniaturizedand the present invention provides a reader/writer capable of improvingthe reliability of communication with IC tags and IC cards and amanufacturing method thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a conventional reader/writer;

FIG. 2 is a schematic diagram showing a relationship between a magneticflux generated from an antenna and an eddy current;

FIG. 3 is a cross-sectional view of a reader/writer according to a firstembodiment of the present invention;

FIG. 4 is a perspective view of the reader/writer shown in FIG. 3;

FIG. 5 is a diagram showing a first step of manufacturing areader/writer according to the first embodiment;

FIG. 6 is a diagram showing a second step of manufacturing areader/writer according to the first embodiment;

FIG. 7 is a diagram showing a third step of manufacturing areader/writer according to the first embodiment;

FIG. 8 is a diagram showing a fourth step of manufacturing areader/writer according to the first embodiment;

FIG. 9 is a diagram showing a fifth step of manufacturing areader/writer according to the first embodiment;

FIG. 10 is a diagram showing a sixth step of manufacturing areader/writer according to the first embodiment;

FIG. 11 is a diagram showing a seventh step of manufacturing areader/writer according to the first embodiment;

FIG. 12 is a diagram showing an eighth step of manufacturing areader/writer according to the first embodiment;

FIG. 13 is a diagram showing a ninth step of manufacturing areader/writer according to the first embodiment;

FIG. 14 is a diagram showing a tenth step of manufacturing areader/writer according to the first embodiment;

FIG. 15 is a diagram showing an eleventh step of manufacturing areader/writer according to the first embodiment;

FIG. 16 is a cross-sectional view of a reader/writer according to asecond embodiment of the present invention;

FIG. 17 is a schematic diagram showing a magnetic flux generated from anantenna of a reader/writer according to the second embodiment;

FIG. 18 is a cross-sectional view of a reader/writer according to athird embodiment of the present invention;

FIG. 19 is a diagram showing a first step of manufacturing areader/writer according to the third embodiment;

FIG. 20 is a diagram showing a second step of manufacturing areader/writer according to the third embodiment;

FIG. 21 is a diagram showing a third step of manufacturing areader/writer according to the third embodiment;

FIG. 22 is a diagram showing a fourth step of manufacturing areader/writer according to the third embodiment;

FIG. 23 is a cross-sectional view of a reader/writer according to afourth embodiment of the present invention;

FIG. 24 is a diagram showing a first step of manufacturing areader/writer according to the fourth embodiment;

FIG. 25 is a diagram showing a second step of manufacturing areader/writer according to the fourth embodiment;

FIG. 26 is a diagram showing a third step of manufacturing areader/writer according to the fourth embodiment; and

FIG. 27 is a diagram showing a fourth step of manufacturing areader/writer according to the fourth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention will be describedwith reference to the accompanying drawings.

First Embodiment

FIG. 3 is a cross-sectional view of a reader/writer according to a firstembodiment of the present invention. FIG. 4 is a perspective view of thereader/writer shown in FIG. 3. In FIG. 4, a solder resist 31 is omittedfor ease of understanding the form of an antenna 26.

First, with reference to FIGS. 3 and 4, a reader/writer 10 according tothe first embodiment of the present invention is described. Thereader/writer 10 comprises a circuit board 11, via connection terminals12 and 13, a communication control portion 14, sealing resin 19, a resinlayer 22, a via 25, the antenna 26, and the solder resist 31.

In the circuit board 11, a conductor pattern (not shown in the drawings)is formed including a plurality of lines of wiring, vias, and the like.The circuit board 11 includes a substrate configured to form the viaconnection terminals 12 and 13 and to mount the communication controlportion 14 thereon. The circuit board 11 may employ a printed board, aflexible board, or the like, for example.

The via connection terminals 12 and 13 are disposed on the circuit board11 such that they are electrically connected to the communicationcontrol portion 14. Upper surfaces 12A and 13A of the via connectionterminals 12 and 13 are exposed from the sealing resin 19 and the resinlayer 22. The upper surfaces 12A and 13A of the via connection terminals12 and 13 are electrically connected to the vias 25. Heights H1 and H2of the via connection terminals 12 and 13 are set such that thepositions of the upper surfaces 12A and 13A of the via connectionterminals 12 and 13 are higher than that of the communication controlportion 14.

The via connection terminals 12 and 13 can be formed by depositing a Cuplated film on the wiring of the circuit board 11 in a columnar manneror by installing a columnar copper material, for example.

The communication control portion 14 is mounted on the circuit board 11.The communication control portion 14 transmits/receives information withIC tags and functions as the reader/writer 10 together with the antenna26. The communication control portion 14 includes a control circuitportion 15, an RF circuit portion 16, and a matching circuit portion 17.The control circuit portion 15, the RF circuit portion 16, and thematching circuit portion 17 are installed on the circuit board 11, andthey comprise a semiconductor chip and a passive element such as LCRconnected to the wiring (not shown in the drawings) of the circuit board11, for example.

The control circuit portion 15 controls the RF circuit portion 16 andperforms communication with the IC tags in accordance with acommunications protocol. The control circuit portion 15 also functionsas an interface between a host computer (not shown in the drawings) andthe reader/writer 10.

The RF circuit portion 16 includes a transmission portion for encodinginformation to be transmitted to the IC tags and modulating carrierwaves (electromagnetic waves), an electric power amplifying portion forsupplying the IC tags with electric power, and a receiving portion fordemodulating information received from the IC tags.

The matching circuit portion 17 is configured to adjust the frequenciesof the carrier waves used for communication and the impedance ofinput/output.

The sealing resin 19 is used to seal the communication control portion14 and disposed so as to cover the control circuit portion 15, the RFcircuit portion 16, and the matching circuit portion 17. In the sealingresin 19, opening portions 21 for exposing the upper surfaces 12A and13A of the via connection terminals 12 and 13 are formed.

The sealing resin 19 is used to protect the communication controlportion 14 from an external impact and the like. The sealing resin 19has a smooth surface and roughening the surface thereof is difficult.Thus, the sealing resin 19 has a poor adhesiveness to a conductive filmformed by a plating method or a sputtering method, so that theconductive film is detached. Accordingly, it is difficult to directlyform the conductive film and dispose the antenna 26 on the sealing resin19. The sealing resin 19 may employ mold resin, for example. The moldresin generally includes much filler component (not less than 70 wt %).Thus, even when a roughening process is conducted so as to haveadhesiveness to plating, the filler is dropped off (collapsed) and anadhesive structure cannot be maintained. In this case, when the platingis applied on the mold resin, the peel strength is as low as 20 to 60g/cm (the plating is readily peeled off). The mold resin may employepoxy mold resin formed by a transfer molding method. The epoxy moldresin includes general epoxy resin into which a softener (phenolicnovolak resin) and a filler (fused silica, crystalline silica, or thelike) are mixed, for example. A diameter D1 of an upper end of theopening portion 21 may be 30 μm to 500 μm, for example.

The resin layer 22 has a higher adhesiveness to the conductive film tobe used as the antenna 26 than that of the sealing resin 19. Also, theresin layer 22 is capable of roughening and disposed so as to cover anupper surface of the sealing resin 19. By stacking the resin having agood adhesiveness to plating on the mold resin, when the plating isapplied on an upper surface of the resin, the peel strength is not lessthan 600 g/cm and the adhesiveness to the plating is improved. The resinlayer to be stacked on the mold resin may employ epoxy resin, phenolicresin, liquid crystal polymer resin, polyimide resin, or the like. Forexample, when thermosetting epoxy resin is used as the resin layer, theepoxy resin is sufficiently adhered to the mold resin by thermosetting.In the resin layer 22, opening portions 23 for exposing the uppersurfaces 12A and 13A of the via connection terminals 12 and 13 areformed. The resin layer 22 may employ epoxy resin; for example. Athickness M1 of the resin layer 22 may be 20 μm to 60 μm, for example.Further, an opening diameter D2 of an upper end of the opening portion23 may be 20 μm to 400 μm, for example.

In this manner, by disposing the resin layer 22 on the sealing resin 19,the resin layer 22 having a higher adhesiveness to the conductive filmto be used as the antenna 26 than that of the sealing resin 19 andcapable of roughening, it is possible to roughen the surface of theresin layer 22 and form the antenna 26 on the resin layer 22. Moreover,it is possible to improve the adhesiveness between the resin layer 22and the antenna 26.

The resin layer 22 may employ resin such as epoxy resin in whichmetallic particles such as Pd used as a catalyst for plating aredispersed, for example. This improves the adhesiveness between theconductive film (plated film) disposed on the resin layer 22 and theresin layer 22.

The via 25 is disposed at the opening portion 23 formed on the resinlayer 22. A lower end of the via 25 is electrically connected to one ofthe via connection terminals 12 and 13. An upper end of the via 25 iselectrically connected to one of antenna portion connection terminals 28and 29. The via 25 is used to electrically connect the via connectionterminals 12 and 13 to the antenna 26.

The antenna 26 is configured to supply IC tags with electric power andtransmit/receive information via electromagnetic induction. The antenna26 is formed on the resin layer 22.

In this manner, by disposing the antenna 26 on the resin layer 22disposed on the sealing resin 19, it is possible to reduce the size(area) of the circuit board 11 as compared with the conventional circuitboard 101 and miniaturize the reader/writer 10.

The antenna 26 includes an antenna portion 27 and the antenna portionconnection terminals 28 and 29. A thickness M2 of the antenna 26 may be10 μm to 25 μm, for example.

The antenna portion 27 has a spiral shape and one end portion isconnected to the antenna portion connection terminal 28 and the otherend portion is connected to the antenna portion connection terminal 29.The antenna portion connection terminal 28 is disposed on the resinlayer 22 and electrically connected to the via 25 connected to the viaconnection terminal 12. The antenna portion connection terminal 29 isdisposed on the resin layer 22 and electrically connected to the via 25connected to the via connection terminal 13. The antenna portionconnection terminals 28 and 29 electrically connect the antenna portion27 to the via connection terminals 12 and 13 via the vias 25.

The solder resist 31 is disposed on the resin layer 22 so as to coverthe antenna 26. The solder resist 31 is used to protect the antenna 26from an external impact and the like.

FIGS. 5 to 15 are diagrams showing steps for manufacturing areader/writer according to the present embodiment. In FIGS. 5 to 15, thesame components as in the reader/writer 10 shown in FIG. 3 are providedwith the same numerical reference.

In the following, a method for manufacturing the reader/writer 10according to the present embodiment is described with reference to FIGS.5 to 15.

First, as shown in FIG. 5, the via connection terminals 12 and 13 areformed on the circuit board 11, and then the communication controlportion 14 (the control circuit portion 15, the RF circuit portion 16,and the matching circuit portion 17) is mounted on one side of thecircuit board 11 on which the via connection terminals 12 and 13 areformed (a step of mounting the communication control portion). In thiscase, the height H2 of the via connection terminal 13 is formed to so asto have substantially the same height as the height H1 of the viaconnection terminal 12.

The via connection terminals 12 and 13 can be formed by depositing a Cuplated film on the wiring of the circuit board 11 in a columnar manneror by installing a columnar copper material, for example.

Next, as shown in FIG. 6, the sealing resin 19 is formed so as to coverthe via connection terminals 12 and 13 and the communication controlportion 14 (a step of forming the sealing resin). A thickness M3 fromthe upper surfaces 12A and 13A of the via connection terminals 12 and 13to an upper surface 19A of the sealing resin 19 may be 10 μm to 600 μm,for example.

Next, as shown in FIG. 7, the opening portions 21 for exposing the uppersurfaces 12A and 13A of the via connection terminals 12 and 13 areformed on the sealing resin 19. The opening portions 21 are formed bylaser processing, drill processing, or the like, for example. Furtherthe diameter D1 of the upper end of the opening portion 21 may be 30 μmto 500 μm, for example.

Next, as shown in FIG. 8, the resin layer 22 for filling the openingportion 21 and covering the upper surface 19A of the sealing resin 19 isformed (a step of forming the resin layer). The thickness M1 of theresin layer 22 may be 20 μm to 60 μm, for example.

The resin layer 22 may employ epoxy resin, for example. When a resinfilm is used as the resin layer 22, for example, the resin layer 22 canbe pressure-bonded to the sealing resin 19 by heating/applying pressureusing a vacuum laminating machine. The resin layer 22 may be formed bycoating the sealing resin 19 with liquid resin and then heat-curing theliquid resin. The resin layer 22 may employ resin such as epoxy resin inwhich metallic particles such as Pd used as a catalyst for plating aredispersed, for example.

Next, as shown in FIG. 9, the opening portions 23 for exposing the uppersurfaces 12A and 13A of the via connection terminals 12 and 13 areformed on the resin layer 22. Thereafter, the surface of the resin layer22 is roughened through desmear process. The opening portions 23 areformed by laser processing, drill processing, or the like, for example.The opening diameter D2 of the upper end of the opening portion 23 maybe 20 μm to 400 μm, for example.

In this manner, the resin layer 22 having a higher adhesiveness to theconductive film than that of the sealing resin 19 is formed on thesealing resin 19 difficult to be roughened because of the smooth surfacethereof and having a poor adhesiveness to the conductive film formed bya plating method, a sputtering method or the like. Thus, it is possibleto roughen the resin layer 22 and form the antenna 26 on the resin layer22.

Next, as shown in FIG. 10, a seed layer 33 is formed on the resin layer22 and on the upper surfaces 12A and 13A of the via connection terminals12 and 13 exposed at the opening portions 23. The seed layer 33 mayemploy a Cu layer formed by an electroless plating method, for example.

Next, as shown in FIG. 11, a resist layer 34 including opening portions34A and 34B is formed on the seed layer 33. The opening portions 34Acorrespond to areas where the antenna portion 27 is formed and theopening portions 34B correspond to areas where the antenna portionconnection terminals 28 and 29 are formed.

Next, as shown in FIG. 12, a conductive metallic film 35 is formed onthe seed layer 33 exposed at the opening portions 34A and 34B.Accordingly, the via 25 including the seed layer 33 and the conductivemetallic film 35 is formed at the opening portions 23. The conductivemetallic film 35 may employ a Cu film formed by an electrolytic platingmethod, for example. The thickness M2 of the conductive metallic film 35may be 10 μm to 25 μm, for example.

Next, as shown in FIG. 13, the resist layer 34 is removed using a resistreleasing agent. Then, as shown in FIG. 14, the seed layer 33 is removedfrom a portion where the conductive metallic film 35 is not formed,thereby forming the antenna 26 (the antenna portion 27 and the antennaportion connection terminals 28 and 29) including the seed layer 33 andthe conductive metallic film 35 (a step of forming the antenna).

In this manner, by forming the antenna 26 on the resin layer 22 formedon the sealing resin 19, it is possible to miniaturize the reader/writer10.

Thereafter, as shown in FIG. 15, by forming the solder resist 31 on theresin layer 22 so as to cover the antenna 26, the reader/writer 10 ismanufactured.

As mentioned above, according to the present embodiment, the resin layer22 having a higher adhesiveness to the conductive film as the antenna 26than that of the sealing resin 19 is disposed on the sealing resin 19for sealing the communication control portion 14 and the antenna 26 isdisposed on the resin layer 22. Thus, it is possible to reduce the size(area) of the circuit board 11 as compared with the conventional circuitboard 101 and miniaturize the reader/writer 10.

In the present embodiment, the method for manufacturing thereader/writer 10 is described based on a case where the antenna 26 isformed by a plating method as an example. However, the antenna 26 may beformed by a vacuum deposition method, a sputtering method, a CVD method,or the like besides the plating method. Moreover, the via 25 maydirectly be connected to the wiring of the circuit board 11 withoutdisposing the via connection terminals 12 and 13.

Second Embodiment

FIG. 16 is a cross-sectional view of a reader/writer according to asecond embodiment of the present invention. FIG. 17 is a schematicdiagram showing a magnetic flux generated from an antenna of thereader/writer according to the present embodiment. In FIGS. 16 and 17,the same components as in the reader/writer 10 according to the firstembodiment are provided with the same numerical reference. In FIG. 17,the solder resist 31 is omitted.

In the following, a reader/writer 40 according to the second embodimentof the present invention is described with reference to FIGS. 16 and 17.The reader/writer 40 includes the circuit board 11, the via connectionterminals 12 and 13, the communication control portion 14, the sealingresin 19, a soft magnetic resin layer 41, the via 25, the antenna 26,and the solder resist 31. In other words, the reader/writer 40 has thesame structure as in the reader/writer 10 except for the soft magneticresin layer 41 disposed in place of the resin layer 22 disposed on thereader/writer 10 according to the first embodiment.

The soft magnetic resin layer 41 is disposed between the sealing resin19 and the antenna 26 so as to cover the upper surface of the sealingresin 19. In the soft magnetic resin layer 41, opening portions 42 forexposing the upper surfaces 12A and 13A of the via connection terminals12 and 13 are formed. The soft magnetic resin layer 41 includes resincontaining soft magnetic metallic powder. The aforementioned resin mayemploy epoxy resin, for example. The soft magnetic metallic powder mayemploy a metal with an initial permeability of not less than one.Preferably, the soft magnetic metallic powder includes at least oneselected from a group consisting of Al, Cr, Mn, Fe, Co, Ni, B, Si, Sr,Nb, Mo, Mg, Zn, and Pt, for example. Also, the soft magnetic metallicpowder may employ metallic powder whose surface is coated with aninsulating material such as epoxy resin. Accordingly, it is possible toimprove the insulation properties between the via connection terminals12 and 13 and the antenna 26. A thickness M4 of the soft magnetic resinlayer 41 may be 20 μm to 60 μm, for example. An opening diameter D3 ofan upper end of the opening portion 42 may be 20 μm to 400 μm, forexample.

In this manner, by disposing the soft magnetic resin layer 41 includingthe resin containing the soft magnetic metallic powder between theantenna 26 and the sealing resin 19, a magnetic flux B₃ generated fromthe antenna 26 does not pass through the circuit board 11. This preventsthe generation of an eddy current on the surface of the circuit board11. Thus, the magnetic flux B₃ generated from the antenna 26 is notattenuated, thereby improving the reliability of communication betweenIC tags and the reader/writer 40.

The soft magnetic metallic powder is preferably mixed with the resin asmuch as 10 wt % 70 wt % relative to the resin. When the soft magneticmetallic powder mixed with the resin is less than 10 wt %, the magneticflux B₃ passes through the circuit board 11 and an eddy current isgenerated, so that the magnetic flux B₃ is attenuated. When the softmagnetic metallic powder is more than 70 wt %, the insulation propertiesof the soft magnetic resin layer 41 cannot be provided sufficiently.Preferably, the soft magnetic metallic powder is mixed with the resin asmuch as 50 wt % to 70 wt % relative to the resin.

Preferably, an average particle size of the soft magnetic metallicpowder is 1 μm to 8 μm. When the average particle size of the softmagnetic metallic powder is less than 1 μm, the magnetic flux B₃ passesthrough the circuit board 11 and an eddy current is generated, so thatthe magnetic flux B₃ is attenuated. When the average particle size ofthe soft magnetic metallic powder is more than 8 μm, the soft magneticresin layer 41 becomes fragile.

In addition, when a resin film is used as the soft magnetic resin layer41, for example, the soft magnetic resin layer 41 can be pressure-bondedto the sealing resin 19 by heating/applying pressure using a vacuumlaminating machine. The soft magnetic resin layer 41 may be formed bycoating the sealing resin 19 with liquid resin and then heat-curing theliquid resin.

As mentioned above, according to the present embodiment, by disposingthe soft magnetic resin layer 41 including the resin containing the softmagnetic metallic powder between the circuit board 11 and the antenna26, it is possible to prevent the attenuation of the magnetic flux B₃due to an eddy current, the magnetic flux B₃ being generated from theantenna 26, and to improve the reliability of communication between ICtags and the reader/writer 40.

The reader/writer 40 according to the present embodiment can bemanufactured by the same method as in the reader/writer 10 according tothe first embodiment.

Third Embodiment

FIG. 18 is a cross-sectional view of a reader/writer according to athird embodiment of the present invention. In FIG. 18, the samecomponents as in the reader/writer 40 according to the second embodimentare provided with the same numerical reference.

In the following, a reader/writer 50 according to the third embodimentof the present invention is described with reference to FIG. 18. Thereader/writer 50 includes the circuit board 11, the via connectionterminals 12 and 13, the communication control portion 14, the sealingresin 19, the resin layer 22, the antenna 26, the solder resist 31, thesoft magnetic resin layer 41, and a via 53. In other words, thereader/writer 50 has the structure of the reader/writer 40, in which theresin layer 22 mentioned in the first embodiment is disposed between thesealing resin 19 and the antenna 26 and the via 53 is disposed in placeof the via 25. In the present embodiment, the soft magnetic resin layer41 corresponds to other layer.

In the resin layer 22, opening portions 52 for exposing the uppersurfaces 12A and 13A of the via connection terminals 12 and 13 areformed. A diameter D4 of an upper end of the opening portion 52 may be10 μm to 300 μm, for example.

The via 53 is disposed at the opening portions 52 formed on the resinlayer 22. The via 53 is used to electrically connect the antenna 26 tothe via connection terminals 12 and 13.

In this manner, by disposing the resin layer 22 between the softmagnetic resin layer 41 and the antenna 26, it is possible tosufficiently insulate between the via connection terminals 12 and 13 andthe antenna 26.

FIGS. 19 to 22 are diagrams showing steps for manufacturing areader/writer according to the present embodiment. In FIGS. 19 to 22,the same components as in the reader/writer 50 shown in FIG. 18 areprovided with the same numerical reference.

In the following, a method for manufacturing the reader/writer 50according to the present embodiment is described with reference to FIGS.19 to 22.

First, the processing (the step of mounting the communication controlportion and the step of forming the sealing resin) shown in FIGS. 5 to 7is performed. Next, as shown in FIG. 19, the soft magnetic resin layer41 for filling the opening portion 21 and covering the upper surface 19Aof the sealing resin 19 is formed (a step of forming other resin layer).The thickness M4 of the soft magnetic resin layer 41 may be 20 μm to 60μm, for example.

Next, as shown in FIG. 20, the opening portions 42 for exposing theupper surfaces 12A and 13A of the via connection terminals 12 and 13 areformed. The opening portions 42 may be formed by laser processing, drillprocessing, or the like, for example. The opening diameter D3 of theupper end of the opening portion 42 may be 20 μm to 400 μm, for example.

Next, as shown in FIG. 21, the resin layer 22 for filling the openingportion 42 and covering the upper surface 41A of the soft magnetic resinlayer 41 is formed (the step of forming the resin layer). The resinlayer 22 is capable of roughening through a desmear process or the like.

Next, as shown in FIG. 22, the opening portions 52 for exposing theupper surfaces 12A and 13A of the via connection terminals 12 and 13 areformed on the resin layer 22. Thereafter, the surface of the resin layer22 is roughened through the desmear process. The opening portions 52 maybe formed by laser processing, drill processing, or the like, forexample. The diameter D4 of the upper end of the opening portion 52 maybe 10 μm to 300 μm, for example.

Thereafter, by performing the same processing as in the steps shown inFIGS. 10 to 15 described in the first embodiment, the reader/writer 50is manufactured.

As mentioned above, according to the present embodiment, the reliabilityof communication between IC tags and the reader/writer 50 is improvedusing the soft magnetic resin layer 41. And it is possible tosufficiently insulate between the via connection terminals 12 and 13 andthe antenna 26 using the resin layer 22 disposed between the softmagnetic resin layer 41 and the antenna 26.

Fourth Embodiment

FIG. 23 is a cross-sectional view of a reader/writer according to afourth embodiment of the present invention. In FIG. 23, the samecomponents as in the reader/writer 50 according to the third embodimentare provided with the same numerical reference.

In the following, a reader/writer 60 according to the fourth embodimentof the present invention is described with reference to FIG. 23. In thereader/writer 60, the sealing resin 19 and the soft magnetic resin layer41 are sequentially stacked, and then opening portions 61 for exposingthe upper surfaces 12A and 13A of the via connection terminals 12 and 13are disposed on the sealing resin 19 and the soft magnetic resin layer41. Except for these elements, the reader/writer 60 has the samestructure as that of the reader/writer 50 according to the thirdembodiment. A diameter D5 of an upper end of the opening portion 61 maybe 30 μm to 500 μm, for example.

FIGS. 24 to 27 are diagrams showing steps for manufacturing areader/writer according to the present embodiment. In FIGS. 24 to 27,the same components as in the reader/writer 60 shown in FIG. 23 areprovided with the same numerical reference.

Next, the reader/writer 60 according to the fourth embodiment isdescribed with reference to FIGS. 24 to 27.

First, the steps (the step of mounting the communication control portionand the step of forming the sealing resin) shown in FIGS. 5 and 6 areperformed. Next, as shown in FIG. 24, the soft magnetic resin layer 41is formed so as to cover the upper surface 19A of the sealing resin 19(a step of forming other resin layer).

Next, as shown in FIG. 25, the opening portions 61 for exposing theupper surfaces 12A and 13A of the via connection terminals 12 and 13 areformed on the sealing resin 19 and the soft magnetic resin layer 41. Theopening portions 61 may be formed by laser processing, drill processing,or the like, for example. The diameter D5 of the upper end of theopening portion 61 may be 30 μm to 500 μm, for example.

Next, as shown in FIG. 26, the resin layer 22 for filling the openingportion 61 and covering the upper surface 41A of the soft magnetic resinlayer 41 is formed (the step of forming the resin layer). The resinlayer 22 is capable of roughening through a desmear process or the like.

Next, as shown in FIG. 27, opening portions 62 for exposing the uppersurfaces 12A and 13A of the via connection terminals 12 and 13 areformed on the resin layer 22. Thereafter, the surface of the resin layer22 is roughened through the desmear process. The opening portions 62 maybe formed by laser processing, drill processing, or the like, forexample. The diameter D4 of the upper end of the opening portion 62 maybe 20 μm to 400 μm, for example.

Thereafter, by performing the same processing as in the steps shown inFIGS. 10 to 15 described in the first embodiment, the reader/writer 60is manufactured.

By manufacturing the reader/writer 60 according to the presentembodiment using the aforementioned method, the steps of forming theopening portions can be reduced to two steps (the opening portions 61and 62) from three steps (the opening portions 21, 23, and 52) in thereader/writer 50 according to the second embodiment, thereby reducingthe manufacturing cost of the reader/writer 60.

The reader/writers as described in the first to fourth embodiments canbe applied to exchanging information with communication media of somekind such as IC cards besides IC tags.

According to the present invention, a reader/writer can be miniaturizedand the present invention can be applied to a reader/writer capable ofimproving the reliability of communication with IC tags and IC cards anda manufacturing method thereof.

The present invention is not limited to the specifically disclosedembodiment, and variations and modifications may be made withoutdeparting from the scope of the present invention.

The present application is based on Japanese priority application No.2005-119866 filed Apr. 18, 2005 the entire contents of which are herebyincorporated herein by reference.

1. A reader/writer comprising: a circuit board; a communication controlportion mounted on the circuit board and configured to performcommunication with IC tags; sealing resin for sealing the communicationcontrol portion; and an antenna electrically connected to thecommunication control portion by an electrode formed within a via,wherein a resin layer is disposed on the sealing resin, the resin layerhaving a higher adhesiveness to a conductive film used as the antennathan that of the sealing resin, and the antenna is disposed on the resinlayer, wherein the via penetrates the resin layer and an internal wallof the via is covered with the resin layer.
 2. The reader/writeraccording to claim 1, wherein the resin layer includes resin containingsoft magnetic metallic powder.
 3. The reader/writer according to claim2, wherein the soft magnetic metallic powder is mixed with the resin asmuch as 10 wt % to 70 wt % relative to the resin.
 4. The reader/writeraccording to claim 2, wherein the soft magnetic metallic powder includesat least one selected from a group consisting of Al, Cr, Mn, Fe, Co, Ni,B, Si, Sr, Nb, Mo, Mg, Zn, and Pt.
 5. The reader/writer according toclaim 2, wherein an average particle size of the soft magnetic metallicpowder is 1 μm to 8 μm.
 6. A method for manufacturing a reader/writerincluding a communication control portion for communicating with ICtags, sealing resin for sealing the communication control portion, andan antenna electrically connected by an electrode formed within a via tothe communication control portion mounted on a circuit board, the methodcomprising the steps of: mounting the communication control portion onthe circuit board; forming the sealing resin; forming a resin layer onthe sealing resin, the resin layer having a higher adhesiveness to aconductive film used as the antenna than that of the sealing resin; andforming the antenna on the resin layer, wherein the via penetrates theresin layer and an internal wall of the via is covered with the resinlayer.
 7. The reader/writer according to claim 1, wherein the viaextends into a depth of the sealing resin and is covered by the resinlayer in the depth of the sealing resin.
 8. The method for manufacturinga reader/writer according to claim 6, wherein the via extends into adepth of the sealing resin and is covered by the resin layer in thedepth of the sealing resin.